The purpose of this project is to study the tolerance of normal tissues in dog to intra-operative radiation therapy. This project is being done to be able to determine tolerance levels, and organs likely to be at risk from intra-operative radiation therapy when given for human abdominal neoplasms. Canine abdomens have been opened and then given single large doses of radiation to a treatment volume similar to which would be performed in humans. Some animals had vascular anastomoses irradiated. The animals were then followed to determine sites of potential radiation damage and tolerance dose levels.